1. Field of the Invention
This invention relates to optical reflectors and more particularly to an optical reflector comprising multiple optical reflector cells, each being individually cooled.
2. Description of the Prior Art
A mirrored or polished front surface of an optical reflector is commonly used to reflect or direct an incident optical wavefront in a desired direction. The source of the optical wavefront may be a relatively high power laser. Reflector front surface properties, such as surface roughness, cause a portion of the incident optical wavefront to be abosrbed by the reflector. The absorbed optical energy is converted to thermal energy which is transferred through the reflector by conduction. The thermally induced temperature increase in the reflector establishes thermal compressive stresses which distort the shape or linearity of the reflector front surface causing errors in the direction of the reflected optical wavefront.
Prior art methods of cooling or dissipating the thermal energy induced on the reflector front surface include fins or radiators connected to the back surface of the reflector. The fins or radiators serve as a heat sink which permits radiation of the induced thermal energy but do not effectively prevent reflector front surface distortions.
Other prior art cooling methods include a flow of a fluid or coolant under relatively high pressure against the back surface of the reflector. However, such methods are not desirable in certain applications involving reflectors having a relatively large reflector front surface and requiring excessive coolant flow under relatively high pressure.